linux-kernel - Re: [PATCH 3/3] cpuidle/menu: add per cpu pm_qos_resume

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Date:   Fri, 20 Jan 2017 16:35:51 +0800
From:   Alex Shi <alex.shi@...aro.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Rik van Riel <riel@...hat.com>
Subject: Re: [PATCH 3/3] cpuidle/menu: add per cpu pm_qos_resume_latency
 consideration



On 01/20/2017 05:43 AM, Rafael J. Wysocki wrote:
> The above may be problematic if the constraints change relatively
> often.  It is global and it will affect all of the CPUs in the system
> every time and now think about systems with hundreds of them.

Yes, the disadvantage is waking up all idle cpus when value changed. As
to the multi core concern, maybe a per cpu notifier way is better? But
that's another story of pm_qos...

So Rafael, any comments for this patch version?

Regards
Alex